Electrolyte for primary batteries.



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ARTHUR P. MANCHESTER, 0F PROVIDENCE, RHODE ISLAND.

ELEGTROLYTE FOR PRIMARY BATTERIES.

No Drawing.

alkaline characteristics, gelatinous in nature and a minimum causticity.

A further object is to provide an electrolyte with which theelectromotive force of the battery will be maintained and local actionreduced when the battery is not in use.

A further object of the invention is to provide an alkaline gelatinouselectrolyte which will maintain its moisture content and stabilitywithout increasing the internal resistance of the battery.

The battery in which the electrolyte is used is preferably one havingzinc positive electrodes and negative electrodesformed I of two copperoxids (cupric oxid and cuprous oxid, for example), as described in thecopending application filed by Harry M. Spooner and myself, Serial No.786,969.

In the making of the electrolyte, sodium hydroxid (NaOH) free from ironand preferably also free from silica is dissolved in water to make asolution of substantially 28 gravity Baum. mixed with the sodiumhydroxid solution. lhe mixing may be efiected by stirring the solutionwith a glass rod, then the solution is heated with occasional stirringuntil it reaches a temperature of approximately 180 F. when the heat isimmediately shut off and the electrolyte stirred thoroughly and allowedto cool to a temperature where it will still flow and may be poureddirectly into the cell, in which it further cools and assumes ajelly-like consistency which does not change materially in the use ofthe cell. The proportions of sodium hydroxid (NaOH), water and starchmay be determined by quantitative analysis; thus such analysis showsthat 1 grs. of starch are required to gelatinize minims or 1 dram ofwater. It also shows that about 10 pounds of sodium hydroxid (NaOH) willmake about 4: gallons of electrolyte at 28 Specification of LettersPatent.

Application filed December 26, 1912.

Vegetable starch is then Patented Apr. 27, 1915.

Serial No. 738,760.

gravity Baum. It also shows that it requires one-sixth as much starch togelatinize the alkaline electrolyte 28 gravity Baum as it does togelatinize water to produce a finished product having about thirtygravity Baum. To give a concrete example, 10 pounds of sodium hydroxid(NaOH) requires approximately 2,731 grs. (specifi' cally 2,7230% grs.)of starch to gelatinize it when in a solution of 28 gravity Baum and 1pound of sodium hydroxid will require approximately 27 3.1 (specifically273.0%) grs. of starch in a solution of 28 gravity Baum.

The temperature to whichthe electrolyte is subiected has been found tobe an important factor but it has been found in treating large batchesof the material when the heat is cut off after the mass reaches atemperature of 180 F. the temperature may continue torise a few degrees,possibly to 190 E, but should not be allowed to exceed 19081. To thisextent the temperature of 180 stated is not to be taken as absolute, yetcare must be taken, first to raise the temperature to a point, where thegelatinizing of the mass will be effective, and at the same time it mustnot be raised to a pointwhere the solution will be discolored or thestarch broken 'down into elements which are formed therefrom at highertemperatures, nor should the temperature beraised to a point where anexcessive quantity of moisture will be driven off, thereby increasingthe specific gravity of the solution. An increase in temperature above190 has been found to be injurious, inasmuch as the efiiciency of theelectrolyte is greatly reduced and an excessive temperature will destroyits usefulness entirely.

The gelatinous electrolyte prevents the mixture of oxide from one plateto another, or, more specifically stated, the zinc'oxid (Z110) is heldagainst or in proximity to the positive electrode, thereby in a measureprotecting the electrode, and the electrolyte being in a gelatinousform, does not soreadily act as a solvent, whereby the creation ofconditions producing counter electromotive force is greatly retarded.The results attained will be understood from a consideration of theaction of the gelatinous electrolyte for, if by chance thenegativeelectrode should disintegrate, with a liquid electrolyte, polarizationof the battery gwould be likely, or a continuous scaling the positiveplate acts as a protective barrier for preventing the electrode frombeing attacked so actively, but without reducing the E. M. -F. becauseitis an oxid of the element used for the electrode. By the re- ,tardationof the solution ofthe Na ZnO- the Whole electrolyte does not becomeimpregnated at once, thus maintaining the E. M. F. for a much longerperiod.

While I have specifically described the use of sodium hydroxid (N aOH)as the al- 'kaline ingredient 'of the electrolyte, I do not Wish to bespecifically limited thereto, .save Where so specified in the claims,inasmuch as it is found that-other alkaline ingredients may be employed,such, for example, as potassium hydroxid, (KOH).

Having thus described my invention, what I claim as new and desiretosecure by Letters Patent of the United States, is:

A gelatinous alkaline electrolyte for primary batteries formed of analkaline hydroxid of approximately 28 gravity Baum with Which vegetablestarch is combined at a temperature of approximately 180 F. and inquantity substantially less than that required to gelatinize an equalquantity 'of ,Water.

2. A gelatinous alkaline electrolyte for 1 primary batteries" formed ofsodium hydroxid' of approximately 28 gravity Baum with which vegetablestarch is combined at a temperatureof approximately 180 F. and inquantity substantially less than that required to gelatinize an equalquantity of' Water.

3. A gelatinous alkaline electrolyte for primary batteries formed of an.alkaline hydroxid of approximately 28 gravity Baum with which vegetablestarch is. combined at a temperature of approximately 180 F, and

in substantially the proportions of approximately 273.1 grs. of. starchto onepound of hydroxid. i Q ARTHUR P. MANCHESTER.

Witnesses; AMos R. Lrrrnn, 1

HARLAN H. BALLARD, Jr.

